The International Fitness Scale (IFIS): Usefulness of self-reported fitness in youth

Francisco B. Ortega, Jonatan R. Ruiz, Vanesa España-Romero, Germán Vicente-Rodriguez, David Martínez-Gómez, Yannis Manios, Laurent Béghin, Dénes Molnar, Kurt Widhalm, Luis A. Moreno, Michael Sjöström, Manuel J. Castillo

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Background: We examined: (i) the usefulness of the International Fitness Scale (IFIS) to correctly rank adolescents into physical fitness levels; (ii) the capacity of the IFIS for predicting cardiovascular disease (CVD) risk; and (iii) the reliability of the IFIS in adolescents. Methods: The study comprised 3059 adolescents (aged 12.5-17.5 years) from nine European countries (HELENA study). Blood samples were collected in one-third of the participants (randomly selected, n=981). Test-retest reliability of the IFIS was studied in a separate sample of 277 adolescents. Physical fitness-cardiorespiratory fitness (CRF), muscular fitness (MF), speed-agility (SP-AG), flexibility and overall fitness-was self-reported using 5-point Likert-scale questions (1=very poor, 5=very good) and measured using standard field-based tests. The CVD risk factors measured included total/central adiposity indices and mean arterial pressure, total and high density lipoprotein cholesterol, triglycerides, insulin resistance (HOMA) and C-reactive protein. Results: Analysis of covariance showed that adolescents reporting better fitness had higher measured fitness levels for all the variables studied (all P<0.001), regardless of gender, age and weight status. Adolescents reporting very good overall fitness, CRF and SP-AG had a healthier cardiovascular profile in eight out of nine CVD risk factors studied. Perfect agreement (same test-retest answer) was observed in 65% of the adolescents and perfect-acceptable agreement (same answer or ±1) in 97% of the adolescents. Conclusions: (i) The IFIS is able to correctly rank adolescents according to their measured physical fitness levels; (ii) adolescents reporting a good/very good overall fitness, CRF or SP-AG have a more favorable cardiovascular profile; and (iii) The IFIS is reliable in adolescents. Published by Oxford University Press on behalf of the International Epidemiological Association.

Original languageEnglish
Article numberdyr039
Pages (from-to)701-711
Number of pages11
JournalInternational journal of epidemiology
Issue number3
Publication statusPublished - Jun 1 2011



  • Adolescent
  • Physical fitness
  • Questionnaires
  • Risk factors
  • Self-report

ASJC Scopus subject areas

  • Epidemiology

Cite this

Ortega, F. B., Ruiz, J. R., España-Romero, V., Vicente-Rodriguez, G., Martínez-Gómez, D., Manios, Y., Béghin, L., Molnar, D., Widhalm, K., Moreno, L. A., Sjöström, M., & Castillo, M. J. (2011). The International Fitness Scale (IFIS): Usefulness of self-reported fitness in youth. International journal of epidemiology, 40(3), 701-711. [dyr039].